Using System Variables

Summary

In MFGStream the concept of the variable has been expanded beyond standard in-code variables to include session-wide variable values which are stored within a terminal session and can be passed between terminal functions. Once a terminal session is closed, the MFGStream variables collection is cleared. That said, a key difference between session variables and environment level variables is the fact that environment variables persist for the lifespan of the environment rather than a given session. Additionally, MFGStream environment variables are read-only while session variables can be written to and read from at any point in a script. That said, session variables are typically destroyed when a terminal session is closed.

Session Variables

Key functions used:

Function
MFGS.Variables.Set
MFGS.Variables.Get

Tip

Prefixing a session variable name with an underscore, _variableName, forces MFGStream to treat this variable as a “global” variable which can be accessed and updated between terminals and sessions.

    Dim value As String
    value = MFGS.Variables.Get("Var1", "Default Value")

    Dim myString As String
    myString = "This is a test value"
    MFGS.Variables.Set("Var1", myString)

Note

Calling Variables.Set() will update the variable if it exists, otherwise MFGStream will create the variable in the given session context.

Environment Variables

As the name implies, this type of variable exists at the MFGStream environment (server) level and are created/destroyed with environment startups and shutdown. Additionally, environment variables are shared across all terminal sessions and are read-only from within MFGStream scripts.

Key functions used:

Function
MFGS.Environment.Get

    Dim environmentValue As String
    environmentValue = MFGS.Environment.Get("EnvVar1", "Default Value", "CategoryName")

Note

As with session level variables, the default value is returned by MFGStream if the named variable cannot be found in the given environment.